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OPERATION TERMINATING MECHANISM Original Filed Jan. 25, 1951 14Sheets-Sheet 14' FIS-lg:

zoo Kass M l INVENTOR. ANTHONY B. MACHADO BY l/QMJXA uw United StatesPatent O oPERATIoN TERMINATING MECHANISM Anthony B. Machado, SauLeandro, Calif., assiguor to Friden Calculating Machine Co., Inc., acorporation of California Continuation of application Serial No.207,782, January 25, 1951, which was a continuation-impart ofapplication Serial No. 2,663, January 16, 1948, in turn a division ofapplication Serial No. 666,966, May 3, 1946. This application October15, 1951, Serial No. 251,311

13 Claims. (Ci. 23S- 73) This invention relates to calculating machinesand particularly machines which are adapted to perform addition,subtraction, multiplication and division. This application is acontinuation of my application led January 25, 1951, entitledCalculating Machines, S. N. 207,782,

abandoned subsequent to the tiling hereof, which applic cation was acontinuation-impart of application S. N. 2,663, tiled January 16, 1948,now abandoned, which was a division of application S. N. 666,966, filedMay 3, 1946, which application was abandoned in favor ofcontinuationin-part application S. N. 164,765, filed May 27, 1950, nowPatent No. 2,650,761.

For purposes of disclosure the invention will be shown embodied in amachine of the type disclosed in the following patents: Patent No.2,229,890, issued to Carl M. F. Friden on January 28, 1941, forAutomatic Division; Patent No. 2,363,737, issued to Anthony B. Machadoon November 28, 1944, for Dividend Entry and Return Clear; Patent No.2,371,752, issued to Carl M. Friden on March 20, 1945, for AutomaticMultiplication; Patent No. 2,399,917, issued to Carl M. Friden andAnthony B. Machado on May 7, 194 6, for Improved AutomaticMultiplication; Patent No. 2,427,271 of Carl M. Friden and Anthony B.Machado, dated September 9, 1947, for Rapid Correction.

Parts of the mechanism disclosed in the above patents associated withthe mechanism of this invention are disclosed herein in order to showthe environment of the novel structure. For a full disclosure of any ofthese mechanisms reference is to be had to the patents cited.

OBJECTS An object of the invention is to provide an improved mechanismfor correlatively controlling a division stopping apparatus and akeyboard clearing apparatus.

Another object of the invention is to provide a calculating machinecapable of automatically performing division operations comprising acontrol member actuatable for stopping a division operation selectivelyin a current cycle, or after a true quotient has been registered, andmechanism controlled by the member for preventing clearing of themachine keyboard when the division operation is stopped by actuation ofthe control member.

.Other objects will be evident after the following disclosure in which:

Fig. l is a perspective view of the machine in which the invention isembodied.

Figs. 2A and 2B taken together comprise a vertical longitudinal sectionthru the machine, the plane of the section is indicated by the line 2-2in Fig. 1.

Figs. 3A and 3B taken together constitute a transverse section taken asindicated by the line 3 3 in Figs. 2A and 2B.

Fig. 4 is a view similar to Fig. 3B in which certain parts have beenomitted and other parts have been added.

Fig. 5 is a fragmentary sectional view showing the power setting unit,the location of the section being indicated by the lines 5-5 in Fig. 3B.

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Fig. 6 is a view taken on the other side of the unit, the location ofthe section being indicated by the line 6-6 in Fig. 3B.

Fig. 7 is a sectional View with parts omitted to show mechanismassociated with the dividend entry and the return clear key, thelocation of the section being indicated on line 7 7 in Fig. 1.

Fig. 8 is a section similar to that in Fig. 7 but with certain partsomitted and others added for the sake of clarity.

Fig. 9 is a view taken from the other side of the frame on which theparts of Fig. 8 are mounted.

Fig. 10 is a fragmentary longitudinal section taken as indicated by theline 10-10 in Fig. 1.

Fig. 11 is a vertical section taken as indicated by the line 11-11 inFig. l.

Fig. 12 is a vertical section taken as indicated by the line 12-12 inFig. 1.

Fig. 13 is a fragmentary view of certain parts shown in Fig. 12 in adifferent position.

Fig. 14 is a vertical section taken as indicated by the line 14-14 inFig. 1.

GENERAL DESCRIPTION Referring to Figure 1, the machine is provided witha main keyboard in which the operator sets the values which are to beregistered in the accumulator 101. The number of registrations iscounted in the revolutions counter 102. Both the accumulator 101 and thecounter 102 are disposed in a shiftable carriage 103. Shifting of thecarriage is controlled by manipulation of left and right shift keys 104,105, respectively. Positive and negative registration of the values setin the keyboard 100 is controlled by plus and minus keys 106, 107.

Keyboard `100 may be manually corrected by depression of keyboard clearkey 109. Add key when preset in a depressed position causes the keyboard 100 to be automatically cleared at the conclusion of an operation.Values registered in the accumulator 101 may be manually clearedtherefrom by means of knob 111, and values registered in the counter 102may be manually cleared therefrom by means of knob 112. An automaticreturn clear operation can be initiated by depressing return clear key113 which causes the carriage to be shifted by power to the left-endposition where the accumulator and counter clear mechanisms may beautomatically operated.

Automatic division operation may be initiated by depressing control keys114. For a full disclosure of the mechanism controlled by the automaticdivision key reference is to be had to the patent to Friden No.2,229,890. To facilitate the performance of a division operation adividend entry key 115 is provided and also tabulator keys 116 on thecarriage 103. When it is desired to enter the dividend in apredetermined ordinal position of the carriage the appropriate tabulatorkey 116 is depressed, then the operator sets the dividend value in thekeyboard 100 and depresses the dividend entry key 115 which initiates anautomatic operation which comprises rst, a return clear operationfollowed by a right shift to the position determined by the depressedtabulator key 116 where the dividend value set in the keyboard 100 isautomatically entered in the accumulator 101. For a full disclosure ofthis mechanism reference is to be had to the patent to Machado 2,363,737referred to above.

In the performance of division operations it is often desirable toterminate the operation before the carriage 103 reaches the left-endposition. This may be because the operator notices that he has obtainedsuicient gures in the counter 102 to give him a satisfactorily accurateanswer, or because he notices that some error has been made in settingthe value in the keyboard. In either event the operator is provided witha lever which, when moved rearwardly from its normal neutral positionwill cause the machine to come to a stop at the end of a cycle in whichthe lever is moved. The lever is usually used in this manner when forsome reason the operator wishes to instantly terminate the operation.However, in the case where the operator has obtained sufficientsignificant figures in the quotient and desires to stop the divisionoperation it is desirable that the machine conclude determination of thequotient figure in the order in which the machine is operating at thetime the lever is moved. This is effected by moving the lever 128forwardly which results in the divisor being subtracted until theoverdraft occurs, at the conclusion of the correction the operation isstopped, thereby providing the operator with an indication in thecounter 182 of true figures of the quotient to the extent determined.

Referring now to the automatic multiplier side of the machine. A ten keykeyboard 121 is provided by means of which the multiplier value is setin a control mechanism which includes indicator dials 122 in which themultiplier value set by means of keyboard 121 is indicated. Inconnection with the automatic multiplier mechanism four operationcontrol keys are provided. The key 123 when depressed causes a returnclear operation followed by the automatic multiplication in which themultiplicand registered in the keyboard 188 is registered in theaccumulator 181 and the multiplier indicated in the dials 122 isregistered in the counter 192, the carriage shifting automatically tothe right as multiplication by each digit is concluded. The control key124 initiates an operation similar to the key 123 except that theaccumulator 101 does not clear. This key is employed whenever it isdesired to preserve the figure registered in the accumulator 101 at theoutset of the multiplication operation. A key 125 initiates an operationsimilar to that of the key 124 except that the registration is negativeinstead of positive, that is, in effect the product of the multiplicandset in the keyboard 180 and the multiplier set in the dials 122 issubtracted from whatever value stands in the accumulator 1111 at thebeginning of the operation. in case the operator decides to change themultiplier figure appearing in the dials 122 before starting amultiplying operation either because the figure was erroneously set upby means of the keyboard 121, or for some other reason, the operator-depresses the key 126 which causes the value to be cleared out of themultiplier control mechanism and to condition the mechanism for reentryof another value by means of the keys 121.

For a complete disclosure of the automatic multiplication mechanismreference is to be had to the patent to Friden 2,371,752 and also to thepatent to Friden et al. 2,399,917 and for an improved mechanismcontrolled by the key 126 reference is to be had to the patent 2,427,271of Friden et al.

GENERAL CONSTRUCTION Frame work o-f the machine comprises a base 130(Fig. 7) at the right side of which is mounted a vertical frame plate131, and at the left side is mounted a vertical frame plate 132 (Figs.3A and 3B). Intermediate the side frames 131, 132 are front and rearbearing plates 133, 134 (Figs. 3A and 3B). These parts comprise the mainframe work of the machine and are supplemented by additional subframes.Supported in the front part of the frame work is the keyboard 18? (Fig.2A). In each ordinal row of keys, well-known means is provided wherebydepression of a selected numeral key adjusts an associated selector gear135 relatively to a segmental differentially stepped tooth actuator drumor gear 136 secured to an actuator shaft 137. After adjustment of thegears 135 rotation of actuator shaft 137 causes the segmental gear 136to engage the selector gear 135 which is rotated a differential amountcorresponding to the number of the key depressed. The selector gears 135are mounted on a square shaft 138 which has a pair of bevel gears 139,140 (Fig. 2B) thereon. The bevel gears 139, 140 are inter-connected by asleeve 141. Transversely extending gate 142 serves to shift all of thesleeves 141 forwardly or rearwardly from their normal central positionshown to engage the bevel gear 140 with the numeral wheel gear 143 or toengage the bevel gear 139 with the numeral wheel gear 143 to determinepositive or negative registration in the accumulator.

Means for rotating the actuator shafts 137 comprises a transverselyextending main drive shaft 145 (Figs. 3A and 3B) which is connected tothe actuator shafts 137 by bevel gears 146, 147. The means for rotatingthe main drive shaft 145 comprises the motor 148 (Fig. 2B) connected bya train of gears 149, 1541, 151 (Fig. 8) to a pawl and ratchet clutch152 the driven side of which is secured to the main drive shaft 145.Cyclic rotation of the drive shaft is determined by operation of aclutch control lever 153 (Fig. 8) pivotally mounted on the frame 131 at154 and connected by a link 155 to a lever 156 pivoted at 157 on theframe 131. The lever 156 has a pin and slot connection 158 to a lever159 pivoted at 160. Lever 159 has a fiber roller 161 for closing thecontacts of the motor switch 162. Accordingly, whenever the roller 161(Fig. 8) is moved rearwardly to close the switch 162 the lever 153 isrocked f to cause engagement of the clutch and the main drive shaft isrotated until the parts are released and permitted to be returned to theposition shown in Figure 8 under the influence of spring 163.

Well-known means is provided for shifting the carriage 103 whichcomprises a pin wheel 170 (Figs. 2B and 3B) which engages a rack on thecarriage and can be selectively rotated in either direction to causeright or left shift by selectively engaging jaw clutches 171, 172respectively. The driver side of each clutch is non-rotatably butslidably mounted on an actuator shaft 137. The right shift clutch 171 isengaged by moving the push rod 173 rearwardly which has a fork 174thereon engaging a groove in the slidable element of the clutch. Aspring 175 normally urges the push rod forwardly to maintain the clutchdisengaged. Similarly, the left shift clutch 172 is controlled by meansof push rod 176.

A well-known means is provided for transmitting power to the clearmechanism for the accumulator and counter. This comprises a jaw clutch177 (Fig. 3A) having an element 178 slidably but non-rotatably mountedon an actuator shaft 137 and moved by means of a push rod 180 having afork 181 engaging a groove in the slidable element of the clutch. Thepush rod is normally urged forwardly by a spring 182 (Fig. ll) to holdthe clutch 177 open.

Power setting unit It will be recalled, referring to Figure l, thatthree of the operation control keys, i. e., return clear key 113,dividend entry key 115 and the multiplication key 123 all cause a returnclear operation, that is, a shift of the carriage to the left endposition where the accumulator is cleared. For that reason theconstruction and operation of the power setting unit will be describedin connection with the return clear key 113.

Referring to Figure 7, return clear key 113 is slidably mounted on studs183 and 184 and when depresed is held down by means of a latch 185 in aWell-known manner. Disposed in an aperture 186 in the key stem is aroller 187 on a bellcrank 188 which is connected by a link 189 to abellcrank thru a pin and slot connection 191.

The link 189 is normally urged rearwardly by means of a spring 192 whichurges the bellcrank 188 counter-clockwise tending to raise the key.

Clockwise rotation of the bellcrank 190 causes clockt wise rotation ofthe shaft 200 by engagement of a roller 291 on the bellcrank with thearm 202 of a lever 203 secured to the shaft 260. The clockwise rockingof the shaft 200 is utilized to close the switch to the motor and toengage the clutch. The mechanism for this is shown 53 in Fig. 9. An arm264 is pinned to the shaft 200. The

arm 264 has a cam face 265 engaging the roller 1561 mounted on the lowerend of the two arm lever 159 (Fig. 8). The rocking of the shaft 211i)causes the surface 265 to cam the roller 161 to close the switch 162 andto rock the clutch dog 153, thereby permitting the clutch to becomeengaged.

rfhe mechanism for lightening the key touch on the operation controlkeys is also associated with shaft 206, and is shown particularly inFigs. and 6. lt will be recalled that depression of the return clear key113, as is true of the other control keys involved herein, rocks theshaft 2th), clockwise in Figs. 6 and 7 and counter-clockwise in Fig. 5.A bellcrank 490 is pinned to the shaft 201i, in a plane adjacent theleft shift clutch push rod 176 (Fig. 3B). The bellcrank 40@ has a lowerarm 401 which is provided with a stud 1102 for the purposes hereinaftermentioned, and an upper arm 403 which is provided with a stud 4M. Thestud 40d is embraced in a slot ll5 in one end of link 4596, a springf-i-tl? connecting stud 404 to the turned-over ear 4% on the adjacentend of the link 466. The other end of link 4116 is pinned to an arm 410of a hook member 411, by any suitable means such as rivet 412. The hookmember 411 is rotatably mounted on an eccentric 413 pinned to the shaft259. The hook member is provided with a second arm 414, the outer end ofwhich is provided with a hook 415.

The shaft 259, just mentioned, is connected at its left end (Fig. 3A),by means of bevel gears 260 to a shaft 261 which in turn is connected bybevel gears 262 (Fig. l2), to main drive shaft 145. 259 is rotated insynchronism with the main drive shaft. It is thus obvious that the hookmember 411 continuously rocks on its eccentric mounting in synchronismwith the main drive shaft whenever the main clutch 152 is engaged andthe motor is running.

A bellcrank ft2@ is pinned to a shaft 25? in a plane irnmediatelyadjacent to that of the hook 415. The upper arm 421 of the bellcrank isprovided with a stud 422 which, when the hook member 411 is rockedclockwise through rocking of the shaft 2116, will be engaged by the Vhook 415 during its continuous reciprocation. However, when the shaft21141 is in its normal setting, the counterclockwise position shown inFig. 6, the reciprocating hook 415 cannot engage the stud 422. When thehook 415 is rocked to its operative position (clockwise of that shown inFig. 6) the hook, at its extreme leftward travel will engage the stud422 and thereupon will rock the bellcrank 42@ and the shaft 25dclockwise. 1t will be understood that the hook 4115 is effective to pullbellcrank 421) and shaft 250 clockwise only after the member 411 hasbeen rocked clockwise on its eccentric, for otherwise the hook will nottravel in a path which will bring it into engagement with stud 422.

The lower arm 423 of the bellcrank 42@ is provided with a latching stud424. Associated with the latching stud 424 is a latching member 425pivotally mounted on a pin 252 supported by the bracket member 426. Thelatch 425 is pulled counterclockwise by a spring 427 tensioned betweenit and the bracket 426. The latch has a shoulder' 428 adapted to engagethe pin 424 on the arm 623, thereby latching the bellcrank 421i andshaft 250 in the operative (clockwise in Fig. 6) position, thus lockingthe shaft in its clutch-engaging position. The latch member 425 is alsoprovided with extension 429 which is engaged by the pin 462 on thebellcrank 400 when the bellcrank and its shaft 200 are rocked in acounter-clockwise direction (in Fig. 6), thereby unlatching the latch425 and releasing the shaft 251) for counter-clockwise rotation. As thebellcrank 420 is locked in its rocked position by the latch 425, therocking of the eccentrically-mounted hook 411 is effective to pull it toits eXtreme latched position and thereafter oscillates idly.

It will be recalled that depression of the return clear key 113 (Fig. 7)causes rotation of the shaft 200 which resulted in the shaft 250 beingrocked to its operative By this means the shaft :as

position. Rocking of the shaft 250 causes engagement of the left shiftclutch and the clear clutch as will now be explained. Referring to Fig.the shaft 250 has an arm 266 secured thereto, on which a pusher arm 268is pivoted by an suitable means, such as pin 267. The pusher arm 268 hasa shoulder 269 engaging a pin 270 on an arm 271 which is secured tosleeve 272 rotatably mounted on a shaft 273 (see also Fig. 3B). Sleeve272 also carries an arm 274 having a pin 275 thereon which engages theleft Shift push rod 176 (Figs. 2A and 3B). This, it will be recalled,causes engagement of the left shift clutch 172 and causes the carriageto be shifted to the left.

The clear clutch is engaged as follows: Referring to Fig. ll shaft hassecured thereto an arm 280, which arm carries a pusher arm 281 pivotallymounted thereon 2. The pusher arm 281 engages a push rod 180 so thatrocking of the shaft 250 also causes engagement of the clear clutch 177(Fig. 3A).

After the conclusion of the return clear operation, a weil-knownmechanism causes operation of the latch (Fig. 7) to release the returnclear key 113. This results in a return of the link 189 under theinfluence of its spring 192 to its original position. Such movement oflink 189 permits return of the bellcrank 19) under the influence of itsspring 283 to its original position, thus, permitting the shaft 201B torock counterclockwise (Fig.

under the influence of spring 284 (Fig. 14) attached to an arm 285secured thereto. Counter-clockwise rotation of the shaft 206 causesunlatching of the arm 425 by reason of engagement of the pin 402 on thearm 401 with the latch 425, for as the shaft 2Q!) and its bellcrank dit@move counter-clockwise (Fig. 6) the pin 402 lifts the latch 25 olf thepin 424 of the arm 423. The lifting of the latch l125 permits thebellcrank 420 to rock counter-clockwise, and, as it is pinned to shaft250, the shaft 25u is likewise rocked counter-clockwise. Thecounterclockwise rocking of shaft 256 disengages the left shift clutchand the clear clutch push rods heretofore described. The release of leftshift clutch push rod 176 (Fig. 3B) and clear clutch push rod 180 (Fig.3A) cause disengagement of their respective clutches under the influenceof their springs. Simultaneously, the release of shaft 2% and itscounter-clockwise rotation, permits spring 163 to cause disengagement ofthe clutch 152 and the opening of switch 162. Shaft 259 is then restoredto its original position by spring 286 (Fig. 3B) and the parts of thepower-setting unit all reoccupy the original position shown in Figs. 5and 6.

Dividend entry Dividend entry key 115 (Fig. 7) when depressed is helddown by means of a well-known latch 290, and thru a pin and slotconnection 291 rocks the bellcrank 19d which, as previously explained,rocks the shaft 200 to release the power setting unit thereby resultingin a return clear operation. As disclosed in the patent to Machado2,363,737, the dividend entry key 115 also conditions mechanism to causea right shift from the left end position to the tabulated positiondetermined by the selected tabulator key 116 (Fig. l) where a cam 292(Fig. 7) is unlatched and is rotated counter-clockwise by a spring 293.rfhe cam 292 engages a roller 294 on a lever 295 secured to a shaft 296(Figs. 2B, 7) which operates the gate 142 previously described to causeentry of the dividend. The lever 295 (Fig. 7) has an upper arm 297 whichengages a pin 298 to withdraw the latch 2% and release the key 115 whichreturns under the influence of its spring 299. Upon return of the key115 the shaft 208 restores, as previously described, and the parts ofthe power setting unit return to their original positions shown inFigures 5 and 6.

Multiplier keys As previously explained, the multiplier key 123 (Fig.

l) causes a return clear operation as a preliminary to initiating amultiplication. Key 123 (Fig. ll) has a pin and slot connection 300 witha lever 361 pivoted to the frame at 362. A roller 303 on the lever 381engages an arm 34M secured to the shaft 2%. Accordingly, depression ofthe key 123 causes rotation of the shaft 251i? and, as previouslydescribed, the power setting unit causes a return clear operation. Asdisclosed in the above cited patent to Friden et al. 2,399,917,mechanism is provided which comes into operation at the conclusion ofthe clear cycle or at the end of a shift of the carriage to the left endposition when no clear cycle is to be performed, and causes rotation ofthe shaft S (Fig. ll). This shaft has an arm 306 secured thereto havingan ear 307 underlying a rearwardly extending arm of a bellcrank 388rotatably mounted on the shaft 250. The other arm of the bellcrank 388has a pin 309 which normally is in engagement with a slot 310 of an arm311 pivoted at 312 on arm E31 secured to the shaft 31d. Shaft (Fig. 14)has secured thereto a latch 315 which, when rotated, releases a pin 316on an arm 317 which, as described in the aforesaid patent, is then freeto rock clockwise and initiate the multiplication operation.

As previously explained, the multiplier keys 124, 1125 do not causeclearing of the accumulator upon return of the carriage to the left endposition. Accordingly, while means are provided to cause operation ofthe power setting unit, additional means is provided under control ofthese keys to override control of the clear mechanism to prevent itsoperation as will now be explained. As explained in the patent to Fridenet a1. 2,399,917, depression of either key 124 or key 125 (Fig. 14)causes rocking of lever 318. ln accordance with this invention lever 318is provided with a depending portion 319 which engages the pin 320 on alever 235 secured to shaft 283 so that depression of either key willrock shaft 2% and cause operation of the power setting unit. The arm 338has a pin 321 engaging the forked end of a link 322 secured to an arm323 fastened to a shaft 324. Referring to Figure ll, shaft 324 also hassecured thereto arm 325 provided with a pin 326 so that upon depressionof either key shaft 324 is rocked counter-clockwise in Figure 14,clockwise in Figure l1 whereupon the pin 326 engages an arm 327 of thepusher arm 281 rocking it counter-clockwise on its pivot 282 to removeit from engagement with the clear clutch push rod 188 so that while theshaft 258 may be rocked, the push rod 189 will not be operated due tothe fact that its control has been removed from the pusher arm 281.

When any one of the keys 123, 124 and 125 is depressed, it is latcheddown during the ensuing multiplying operation and is automaticallyreleased at the end of the operation by known mechanism of the kinddisclosed in the aforesaid Friden Patent 2,399,917.

The multiplier correction key 126 (Fig. ll) has a pin and slotconnection 328 with a bellcrank 329 pivoted at 33S. The depending arm ofthe bellcrank has pin 331 thereon which underlies the end of the arm 311and which lifts the notch 310 out of engagement with the pin 399 whenthe multiplier correction key is depressed. This prevents initiation ofa multiplying operation at the conclusion of the clear cycle at whichtime the shaft 305 is rotated, as previously described. The pin 331 inlifting the rear end of the'arm 311 brings it into engagement with a pin332 (see also Fig. l2) on a fork 333 which, when rocked clockwise, liftsthe return feed pawl 334 into operative engagement with the rack 335 onthe multiplier pin carriage 336. When the key 126 is depressed and thebellcrank 329 is rocked counter-clockwise the shaft 290 is rocked byreason of a. link 337 which interconnects the bellcrank and the arm334i. This, as previously described, causes operation of the powersetting unit and consequently a return clear operation is initiated.However, it is undesirable to cause clearance of the values in theaccumulator in this operation rie-:ted the link d` to the pin 358 (Fig.9).

so the link 337 (Fig. ll) is provided with a pin 338 which engages thearm 327 of the pusher arm 281 in order to move it to inoperativeposition. When the shaft 238 is rocked to initiate the operation, themain drive shaft 14S (Fig. l2) is started rotating, and thru the bevelgear connection 262 rotates the shaft 261 which, it will be recalled,has a bevel gear connection 26) to the shaft 259. Secured to the shaft259 is a cam 339 which is so disposed that when the pin carriage 336 hasbeen ren turned to its farthest right position the cam 339 is incooperative relation with an ear 34) on a lever 341 having a pin 342therein which extends laterally across the indicator dials 122, and asshown in Figure 13 acts as a bail to restore all of the dials to zerowhere they become latched by the latches 343 (Fig. l2).

Disabling keyboard clear lt is desirable when the multiplier correctionkey 126 is depressed that the value set in the keyboard be f: retainedtherein regardless of the adjustment of the add key 118. For this reasonthe lever 329 (Fig. 1l) has a shoulder 358 overlying the end of a lever351 secured to a shaft 352 which extends laterally across the front ofthe machine to the right side where it appears in Figure 8.

The normal operation of the automatic keyboard clear mechanism under thecontrol of the add key 11i) will now be described. Referrinfy to Figure9, when the key is depressed it, by means of a pin and slot connection353 with a long link 35d, lowers the front end of the link 354 which,under control of a cam face 355 thereon with a stud 356 in the frame, ismoved forwardly and downwardly. The downward movement results inengaging a notch 357 in the link 354 with a pin 358, the purpose ofwhich will be presently described. When the link 354 moves forwardly itrocks the foot of a lever 359 pivoted at 338 into the path of a pin 361secured to a member 362 on the main drive shaft so that as the driveshaft 145 rotates counter-clockwise (Fig. 9) the pin 361 rocks the lever359 near the end of the cycle and this causes the link 354 to draw thepin 358 rearwardly. Referring now to Figure 8, pin 358 is secured to abellcrank 363 pivoted at 36?:- to the side frame 131. Pivotally mountedat 36S on the bellcrank 363 is an arm 366 which has a lip 367 on itsfront edge which is adapted to engage an extension 363 on the bail 369(Fig. 2A) which operates the latch slides 37() to release the keys ofthe keyboard. lf the arm 366 is rocked counter-clockwise, in Figure 8,on its pivot, the lip 367 will pass beneath the extension 368 and failto clear the keyboard. The function of the shaft 352 which is rockedclockwise in Figure 8 upon depression of the multiplier correction keycan now be explained. Secured to the right end of the shaft 352 is abellcrank 371 having a fork 372 engaging lug 373 on a lever 374 pivotedat 375. The

E lever 374 has an ear 376 which engages the lip 367 of the arm 366 torock the arm 366 counter-clockwise when the shaft 352 is rotatedclockwise which causes the lip to reciprocate underneath the extension368 if the add key 115.5 is in its depressed position where it has con-In addition, when the add key M8 is depressed the latch 377 is permittedto become operative under the influence of its spring 378 so that whenthe shaft 352 and the bellcrank 371 are rotated clockwise upondepression of the multiplier correction key, the shoulder 379 on thelatch 377 will engage a pin 384! on the bellcrank 371 to hold the arm366 in its inoperative position. On the arm 366 is a square pin 381which engages the hooked end 382 of the latch 377 and unlatches it atthe end of the rearward j stroke of the arm 366 so that in effect, whenthe latch fore the lip 367 is prevented from operating the keyboardclearing bail 363-369 even through the fork 372 is temporarily unlatchedcyclically. During the last cycle of a multiplier correction operation,the multiplier correction key 126 is released prior to the operation ofthe link 354 by the pin 361 and lever 359. During this cycle, after thekey 126 has been released, the latch 377 effectively holds the fork 372in position for maintaining the link 366 inoperative with respect to thekeyboard Clearing bail 368- 369, thus preventing the last cycleoperation of the link 354 from clearing the keyboard.

In the operation of the multiplier keys 123, 124, 125, the return clearkey 113 and the dividend entry key 115, the automatic keyboard clearmechanism is disabled during the operation but is enabled in the lastcycle of the operation. This is effected by the following mechanism. Theshaft 250 (Fig. 9) has secured thereto an arm 383 connected by a link384 to an arm 335 (Fig. 7) pivoted on the side frame 131 at 336 andhaving a link 387 pivoted thereto at 333, the other end of the linkbeing pivoted at 339 to an arm 390 rotatably mounted on the shaft 391.The opstanding end 392 of the link 337 has a pin 393 which is shown insection in Figure 8. Therefore, when any of the operation keys referredto which bring the power setting unit into operation are depressed theshaft 250 is rocked, resulting in elevation of the pin 393 (Fig. 8)thereby rocking the arm 366 to its inoperative position so that duringthe time any of these keys are latched down the keyboard clearingmechanism is inoperative until they are unlatched, which occurs in thelast cycle of the operation when the keyboard clear mechanisrn becomesoperative.

Division stop As previously described, the lever 120 (Fig. l) can bemoved either rearwardly to instantly stop the machine in the currentcycle, or forwardly to conclude a division operation after a truequotient figure has been determined.

Referring now to Figures 8 and 9 and to the previously cited patent toFriden 2,229,890 for details of the automatic division mechanism. Whenthe division keys 114 (Fig. l) are depressed the division operationcontrol member 394 (Fig. S) is rocked counter-clockwise on its pivot. Asexplained in said patent, the forked end of the lever 394 engages a pinon a gate-adjusting slide and moves the latter to adjust the gate 142(Fig. 2B) to the subtract position. When an overdraft occurs means areprovided which move the lever 394 rearwardly to adjust the gate to theadd position, and at the conclusion of the corrective addition cycle thelever 394 is moved forwardly to adjust the gate to neutral during theshift cycle. A latch 395 is adapted to engage a semicircular pin 396 inthe lever 394 when it is rocked counter-clockwise upon depression of thedivision key 114. Latch 39S is urged clockwise on its pivot by a spring397 and has an ear 398 which cooperates with a nose 399 on the lever 120which is pivoted at 400. When the operator moves the lever 120rearwardly to stop the division operation, the lower cam face of thenose 399 engages the ear 398 to rotate the latch 395 thereby releasingthe pin 396. However, when it is desired to terminate the divisionoperation with the true quotient gure the lever 120 is moved forwardlyor counter-clockwise on its pivot 400. An arm 402 is connected to thelever 120 by a spring 403 which urges the arm 402 counter-clockwise onits pivot. The counter-clockwise rotation is limited by an ear 404 onthe arm 402 engaging the lower edge of lever 120. When the lever 120 ismoved counter-clockwise a shoulder 405 on the arm 402 engages theunderside of the ear 398 on the latch 395 and the spring 403 istensioned. At the end of the cycle in which the overdraft occurs the arm394 is moved rearwardly so that the pin 396 causes the latch 395 torotate counter-clockwise. When the ear 398 frees the shoulder 405 thearm 402 is rotated counter-clockwise by its spring 403 until a secondshoulder 406 engages the ear 398. At the end of the cycle of correctiveaddition the lever 394 moves forwardly and the pin 396 moves off thelatch 395 which is held out by the arm 402 so that the arm 394 mayreturn to its original position thereby stopping the division operationafter vthe corrective addition with the true quotient figure in thecounter.

In the well known standard Friden commercial machine, means controlledby the division key is provided for rocking the lever 424counter-clockwise (Fig. 8) to disable the keyboard clearing mechanismduring all but the last cycle of a division operation. During the lastcycle the keyboard clearing mechanism is re-enabled and the keyboard iscleared.

In both division stop operations it is desirable not to clear thekeyboard because the operator may wish to employ the divisor set thereinto continue the division operation. Accordingly, the lever 120 isprovided with a pin 410 which extends thru a slot in the side frame 131and engages in the forked end of a lever 411 (Fig. 9) pivoted at 412.The lever 411 has an ear 413 which engages a lug 414 on an arm 415 whichhas a finger 416 overlying the end of a lever 417 pivoted at 418. Whenthe lever 120 (Fig. 9) is moved rearwardly the pin 410 rocks the lever411 counterclockwise, the arm 415 clockwise and the lever 417counter-clockwise. The parts are held in this position by a latch 420which has a shoulder 421 that engages an ear 422 on the arm 415. Thelever 417 has a pin 423 which extends laterally thru a hole in the sideframe 131 as seen in Figure 8. As there viewed, when the lever 120 ismoved to its rearward position the pin 423 moves upwardly, in so doingit rocks the lever 424 counter-clockwise on its pivot 364 and the lever424 has a pin 425 which rocks a lever 426 clockwise. The lever 426engages a pin 427 on the lever 366 which is rocked counter-clockwise onits pivot 365 thus lowering the lip 367 below the extension 368 so thatif the add key is depressed the lip 367 will move rearwardly beneath theextension 368 as the link 354 (Fig. 9) moves rearwardly. At the end ofits rearward stroke the rear end of the link 354 engages an ear 428formed on an arm of the latch 420 and rotates the latchcounter-clockwisel on its pivot 412 thereby releasing the arm 415.

Even if, during the performance of a cycle in a division operation, thedivision stop lever 120 should be moved rearwardly and then allowed toreturn quickly before the completion of the current cycle, that is,before the pin 361 on the rotary member 362 encounters the lower end ofthe lever 359, the keyboard nevertheless, will not be cleared. This isbecause the latch 420, having been set in latching position by therearward movement of the stop llever 120, will maintain the keyboardclearing mechanism disabled until the end of the last cycle. When thepin 361 rocks the lever 359 at the end of the last cycle, causingreleasing of the latch 420, as previously explained, the lip 367 on thearm 366 will already have passed idly under the extension 368 on thekeyboard clearing bail 369. Consequently, the rocking of the lever 359in the last cycle which releases the latch 420 to render the keyboardclear disabling means ineffective will not cause operation of thekeyboard clear mechanism.

When the lever 120 is moved forwardly it is held in its forward positionby the detent 401 (Fig. 8). Forward movement of the lever 120 (Fig. 9)causes counterclockwise rotation of the lever 411 and sets all of theparts, as previouslydescribed, with the exception of the latch 420 whichis held disabled by engagement of the pin 410 with a lug 429 on thelatch 420.

I claim:

l. In a calculating machine capable of performing division operationsautomatically by the method of successive subtractions, overdraft andcorrective addition, a control member, a latch therefor, said memberbeing moved to latched position when a division operation is initiated,said member remaining latched during the division operation, unlatchingof said member terminating the operation, while latched said membermoving from one position to another to control the subtraction andadditive registrations, a lever manually movable in one of twodirections to selectively terminate a division operation either in thecurrent cycle or as soon as a true quotient figure has been registered,said lever having a face engageable with said latch when said lever ismoved in one direction for moving said latch to release said member,said lever having a pawl thereon rendered operative with respect to saidlatch when said lever is moved in the other direction, said pawl movinginto blocking relation with respect to said latch when said member andlatch move to the additive control position so that upon return of saidmember from the additive position after determination of the truequotient figure said latch is blocked against movement by said pawl andsaid member is released from said latch.

2. In a calculating machine capable of performing automatic division andhaving a keyboard in which the divisor is set and latched, a divisionoperation control member movable from ineffective position to operativeposition for effecting and controlling the performance o f a divisionoperation, an automatically operable keyboard clear means, normallyineffective disabling means adapted when rendered effective to disablesaid keyboard clear means, division stop mechanism including a levermanually movable in one direction or the opposite to effect returning ofsaid division operation control member to ineffective position toselectively terminate the division operation either in the current cycleor as soon as a true quotient figure has been registered, and meansactuated by movement of said lever in either direction for renderingsaid disabling means effective.

3. In a calculating machine capable of performing division operationsautomatically by the method of successive subtractions, overdraft andcorrective addition, a control member, a latch therefor, said memberbeing moved to latched position when a division operation is initiated,said member remaining latched during the division operation, unlatchingof said member terminating the operation, While latched said membermoving from one position to another to control the subtraction andadditive registrations, a lever manually movable in one of twodirections to selectively terminate a division operation either in thecurrent cycle or as soon as a true quotient figure has been registered,said lever being formed with a cam face and said latch having an earengageable by said cam face when said lever is moved in one directionfor moving said latch to release said member, said lever having a pawlthereon rendered operative with respect to said latch when said lever ismoved in the other direction, said pawl moving into blocking relationwith respect to said latch when said member and latch move to theadditive control position so that upon return of said member from theadditive position after determination of the true quotient figure saidlatch is blocked against movement by said pawl and said member isreleased from said latch.

4. In a calculating machine capable of performing division operationsautomatically and having a keyboard in which the divisor is set andlatched, a division operation control member movable from ineffectiveposition to operative position for effecting and controlling theperformance of a division operation, an automatically operable keyboardclear means, a lever manually operable to effect returning of saiddivision operation control member to ineffective position to terminate adivision operation, means actuated by said lever for disabling saidkeyboard clear means, and means responsive to return movement of saidlever for re-enabling said keyboard clear means.

5. In a calculating machine capable of performing automatic division andhaving a keyboard in which the divisor is set and latched, a divisionoperation control member movable from ineffective position to operativeposition for effecting and controlling the performance of a divisionoperation, an automatically operable keyboard clear means, a levermanually movable from a neutral position in one direction or theopposite to effect returning of said division operation control memberto ineffective position to selectively terminate the division operationeither in the current cycle or as soon as a true quotient figure hasbeen registered, means actuated by movement of said lever in eitherdirection for disabling said keyboard clear means, and means responsiveto return movement of said lever to neutral position for reenabling saidkeyboard clear means.

6` In a calculating machine capable of performing automatic division andhaving a keyboard in which the divisor is set and latched, a divisionoperation control member movable from ineffective position to operativeposition for effecting and controlling the performance of a divisionoperation, an automatically operable keyboard clear means, a levermanually movable from a neutral position in one direction or theopposite to effect returning of said division operation control memberto ineffective position to selectively terminate the division operationeither in the current cycle or as soon as a true quotient figure hasbeen registered, means including an element movable in a predetermineddirection for disabling said keyboard clear means, and an operatingconnection between said lever and said element for moving the latter insaid predetermined direction in response to movement of said lever ineither direction from its said neutral position.

7. In a calculating machine capable of performing division operationsautomatically and having a keyboard in which the divisor is set andlatched, keyboard clear means, cyclically operable mechanism foroperating said keyboard clear means automatically following thenextto-last cycle of a division operation, a lever manually operable toterminate a division operation, and disabling means actuatable by saidlever for preventing said mechanism from operating said keyboard clearmeans, a latch for releasably holding said disabling means' in actuatedposition, and means operated by said mechanism for releasing said latch.

8. In a calculating machine capable of performing division operationsautomatically and having a keyboard in which the divisor is set andlatched, a division operation control member movable from ineffectiveposition to operative position for effecting and controlling theperformance of a division operation, an automatically operable keyboardclear means, normally ineffective disabling means adapted when renderedeffective to disable said keyboard clear means, a lever manuallyoperable to effect returning of said division operation control memberto ineffective position for terminating a division operation, and meanactuatable in response to such operation of said lever for renderingsaid disabling means effective, said disabling means being adapted to berendered effective exclusively under the control of said lever.

9. In a calculating machine capable of performing automatic division andhaving a keyboard in which the divisor is set and latched, a divisionoperation control member movable from ineffective position to operativeposition for effecting and controlling the performance of a divisionoperation, keyboard clear means normally operable automaticallyfollowing the neXt-to-last cycle of a division operation, a levermanually movable in one direction or the opposite to effect returning ofsaid division operation control member to ineffective position toselectively terminate the division operation either in the current cycleor as soon as a true quotient figure has been registered, and meansrendered effective by movement of said lever in either direction fordisabling said

